Got locked out of my Stadia app

I recently bought a new phone and now the Stadia app does not give me access to my profile. Instead it’s asking me to input the access code that was sent to me for my founders edition. But when I input the code there’s a message saying that someone else already used it and it’s invalid?? So I have no access to the app or my games or anything? I need someone to help me with this issue please!? Thank you

1. What device are you currently using?2. Is the Google account you used to set up the phone the same one that you signed up for Stadia with?3. Have you tried accessing Stadia on other devices such as a computer to ensure you still have access?